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JXB：西北寒旱所、蘭大丨FADs在植物脅迫耐受中的功能（鈣信號）
作者：中科院西北生態(tài)環(huán)境資源研究所石玉蘭、蘭州大學生科院安黎哲
標題：Integrated regulation triggered by a cryophyte ω-3 desaturase gene confers multiple-stress tolerance in tobacco
主題：ω-3脂肪酸去飽和酶在植物脅迫耐受中的功能
期刊：Journal of Experimental Botany
影響因子：5.354
檢測指標：Ca2+
英文摘要
ω-3 fatty acid desaturases (FADs) are thought to contribute to plant stress tolerance mainly through linolenic acid (C18:3)-induced membrane stabilization, but a comprehensive analysis of their roles in stress adaptation is lacking.
Here, we isolated a microsomal ω-3 FAD gene (CbFAD3) from a cryophyte (Chorispora bungeana) and elucidated its functions in stress tolerance. CbFAD3, exhibiting a high identity to Arabidopsis AtFAD3, was up-regulated by abiotic stresses. Its functionality was verified by heterogonous expression in yeast. Overexpression of CbFAD3 in tobacco constitutively increased C18:3 in both leaves and roots, which maintained the membrane fluidity, and enhanced plant tolerance to cold, drought, and salt stresses.
Notably, the constitutively increased C18:3 induced a sustained activation of plasma membrane Ca2+-ATPase, thereby, changing the stress induced Ca2+ signaling. The reactive oxygen species (ROS) scavenging system, which was positively correlated with the level of C18:3, was also activated in the transgenic lines.
Microarray analysis showed that CbFAD3-overexpressing plants increased the expression of stressresponsive genes, most of which are affected by C18:3, Ca2+, or ROS. Together, CbFAD3 confers tolerance to multiple stresses in tobacco through the C18:3-induced integrated regulation of membrane, Ca2+, ROS, and stress-responsive genes. This is in contrast with previous observations that simply attribute stress tolerance to membrane stabilization.
中文摘要（谷歌機翻）
ω-3脂肪酸去飽和酶（FADs）被認為主要通過亞麻酸（C18：3）誘導的膜穩(wěn)定作用促進植物抗逆性，但缺乏對其在脅迫適應中的作用的綜合分析。
在這里，我們從冷凍植物（Chorispora bungeana）中分離出微粒體ω-3 FAD基因（CbFAD3），并闡明其在脅迫耐受中的功能。表現出與擬南芥AtFAD3高度同一性的CbFAD3被非生物脅迫上調。其功能通過酵母中的異源表達來驗證。煙草中CbFAD3的過量表達在葉和根中組成性地增加了C18：3，這保持了膜的流動性，并增強了植物對冷，干旱和鹽脅迫的耐受性。
值得注意的是，組成型增加的C18：3誘導質膜Ca2+-ATPase的持續(xù)活化，從而改變應激誘導的Ca2+信號傳導。與C18：3水平正相關的活性氧（ROS）清除系統(tǒng)也在轉基因系中被激活。
微陣列分析顯示過表達CbFAD3的植物增加了應激反應基因的表達，其中大多數受C18：3，Ca2+或ROS的影響。 CbFAD3一起通過C18：3誘導的膜，Ca2+，ROS和應激反應基因的整合調節(jié)賦予對煙草中多種脅迫的耐受性。這與先前的觀察結果形成對比，之前的觀察結果僅僅將壓力耐受性歸因于膜穩(wěn)定。
Ca2+ fluxes in root tips treated with 15% PEG or 200 mM NaCl (n=10 ten-day-old seedling roots).